1.0.0.28: more PCL cleanups

1.0.0.28: more PCL cleanups
  * WRAPPER-INSTANCE-SLOTS-LAYOUT and WRAPPER-CLASS-SLOTS are
    a null layer around corresponding %WRAPPER- accessors: rename
    the accessors without % and remove the macros.
  * CACHE-LOCK-COUNT unused, deleted.
  * WRAPPER-OF-MACRO redundant, removed. Use WRAPPER-OF.
  * new function MAKE-DFUN-REQUIRED-ARGS to factor out a shared
    idiom as per FIXME.
  * WITH-HASH-TABLE and WITH-EQ-HASH-TABLE removed: thread unsafe.
  * Commentary.